Etan Patz, left, is seen alongside Pedro Hernandez, 51, who was arrested May 24, 2012 in the boy's 1979 disappearance.

AP/Inside Edition

(CBS/AP) NEW YORK - Pedro Hernandez, the man who has confessed to killing 6-year-old Etan Patz in one of New York City's and the country's most notorious missing child cases, remains in a psychiatric hospital as court-appointed doctors assess his mental state.

Defense lawyers said Hernandez, 51, has schizophrenia and a history of hallucinations and it's unclear how much that will factor in the case charging him with the Etan's 1979 murder.

If Hernandez' psychiatric record becomes an issue, he'll encounter a justice system that seeks to strike a balance between recognizing mental illness and holding people responsible for their actions. It is a balance that has shifted back and forth over more than a century and a half.

Hernandez confessed last week and is now charged with Patz's murder. The boy vanished on his way to school in his lower Manhattan neighborhood. The suspect, who had worked at a convenience store near Etan's home, confessed after hours of police questioning, Police Commissioner Raymond Kelly said on Friday. Kelly said Hernandez told police he lured the boy to the convenience store with the promise of a soda. He then took him into the basement and choked him.

After defense lawyer Harvey Fishbein told a judge that Hernandez was schizophrenic, bipolar, had had visual and auditory hallucinations, and had been on psychiatric medication for some time, the judge ordered an examination to see whether he was mentally fit to stand trial.

The results aren't yet known and either side could challenge the findings and get another exam. It will ultimately be up to a judge to declare whether Hernandez can go to trial. If not, he would be sent to a psychiatric hospital and evaluated periodically to see whether he had improved enough to go to court. Most people found unfit are eventually returned to court, legal experts say.

Such exams aim to assess whether someone is well enough to participate in a trial and aid his or her own defense. They are separate from an insanity defense, which revolves around the defendant's psychological state at the time of the alleged crime.

In New York and many other states, defendants have to prove they were so mentally ill that they didn't know what they were doing was wrong. If successful, they are sent to psychiatric hospitals until judged well enough for release, if ever.

One of Hernandez's sisters, Norma Hernandez, said Tuesday that she went to police in Camden, N.J., years ago to report a rumor he had confessed at a prayer group. Camden police declined to comment on her remarks.

Meanwhile, Etan's father made clear that the attention to the case since Hernandez's arrest last week had taken a toll, telling reporters they had "managed to make a difficult situation even worse."

"It is past time for you to leave me, my family and my neighbors alone," Stan Patz said in a note posted on his apartment building's door.